Android AsyncTask 线程永不消亡
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AsyncTask threads never die
提问by Computerish
I'm using AsyncTasks to fetch data in response to the user pressing a button. This works well and keeps the interface responsive while fetching the data, but when I checked out what was going on in the Eclipse debugger, I found out that every time a new AsyncTaskwas created (which is quite often, because they can only be used once), a new thread was being created but never terminated.
我正在使用AsyncTasks 来获取数据以响应用户按下按钮。这很有效并且在获取数据时保持界面响应，但是当我检查 Eclipse 调试器中发生的事情时，我发现每次AsyncTask创建一个新的（这很常见，因为它们只能使用一次)，正在创建一个新线程，但从未终止。
The result is a large number of AsyncTaskthreads just sitting there. I'm not sure if this is a problem in practice or not, but I'd really like to get rid of those extra threads.
结果是大量AsyncTask线程只是坐在那里。我不确定这在实践中是否存在问题，但我真的很想摆脱那些额外的线程。
How can I kill these threads?
我怎样才能杀死这些线程？
回答by CommonsWare
AsyncTaskmanages a thread pool, created with ThreadPoolExecutor. It will have from 5 to 128 threads. If there are more than 5 threads, those extra threads will stick around for at most 10 seconds before being removed. (note: these figures are for the presently-visible open source code and vary by Android release).
AsyncTask管理一个线程池，用ThreadPoolExecutor. 它将有 5 到 128 个线程。如果线程数超过 5 个，则这些多余的线程最多会停留 10 秒钟，然后再被移除。（注意：这些数字适用于目前可见的开源代码，因 Android 版本而异）。
Leave the AsyncTaskthreads alone, please.
请不要管这些AsyncTask线程。
回答by Tom de Waard
In addition to CommonsWare's response:
除了 CommonsWare 的回应：
Currently I'm using Android 2.2, and my application uses no more than one AsyncTask at any time, but I'm creating a new one every x minutes. At first new AsyncTask Threads start to appear (a new Thread for a new AsyncTask) but after 5 threads (as mentioned by CommonsWare) they just stay visible in the debug window, and get re-used when new AsyncTask threads are needed. They just stay there until the debugger disconnects.
目前我使用的是 Android 2.2，我的应用程序在任何时候使用的 AsyncTask 都不超过一个，但我每 x 分钟创建一个新的。起初，新的 AsyncTask 线程开始出现（一个新的 AsyncTask 的新线程），但在 5 个线程之后（如 CommonsWare 所述），它们只是在调试窗口中保持可见，并在需要新的 AsyncTask 线程时重新使用。他们只是呆在那里，直到调试器断开连接。
回答by karnbo
Same symptom here. In my case the threads hanged around after I'd killed the Activity, and I was hoping for the App to close completely. Problem partly solved by using a single threaded executor:
这里的症状相同。在我的情况下，线程在我杀死 Activity 后挂起，我希望应用程序完全关闭。通过使用单线程执行器部分解决了问题：
myActiveTask.executeOnExecutor(Executors.newSingleThreadExecutor());
This made the thread to vanish after the completing its work.
这使得线程在完成其工作后消失。
回答by Ravindra babu
Use ThreadPoolExecutor.
BlockingQueue workQueue= new LinkedBlockingQueue<Runnable>(100); // Work pool size
ThreadPoolExecutor executor = new ThreadPoolExecutor(
Runtime.getRuntime().availableProcessors(), // Initial pool size
Runtime.getRuntime().availableProcessors(), // Max pool size
1, // KEEP_ALIVE_TIME
TimeUnit.SECONDS, // KEEP_ALIVE_TIME_UNIT
workQueue);
Post your Runnabletask by using execute()method.
Runnable使用execute()方法发布您的任务 。
void execute (Runnable command)
Executes the given task sometime in the future. The task may execute in a new thread or in an existing pooled thread
在未来的某个时间执行给定的任务。任务可以在新线程或现有池线程中执行
Regarding your second query:
关于您的第二个查询：
How can I kill these threads?
我怎样才能杀死这些线程？
Once you are done with all your work with ThreadPoolExecutor, shutdown it properly as quoted in below post:
完成所有工作后ThreadPoolExecutor，请按照以下帖子中的引用正确关闭它：
